Globally distributed iridium layer preserved within the Chicxulub impact structure

The Cretaceous-Paleogene (K-Pg) mass extinction is marked globally by elevated concentrations of iridium, emplaced by a hypervelocity impact event 66 million years ago. Here, we report new data from four independent laboratories that reveal a positive iridium anomaly within the peak-ring sequence of the Chicxulub impact structure, in drill core recovered by IODP-ICDP Expedition 364. The highest concentration of ultrafine meteoritic matter occurs in the post-impact sediments that cover the crater peak ring, just below the lowermost Danian pelagic limestone. Within years to decades after the impact event, this part of the Chicxulub impact basin returned to a relatively low-energy depositional environment, recording in unprecedented detail the recovery of life during the succeeding millennia. The iridium layer provides a key temporal horizon precisely linking Chicxulub to K-Pg boundary sections worldwide

Prenatal exposures and exposomics of asthma

This review examines the causal investigation of preclinical development of childhood asthma using exposomic tools. We examine the current state of knowledge regarding early-life exposure to non-biogenic indoor air pollution and the developmental modulation of the immune system. We examine how metabolomics technologies could aid not only in the biomarker identification of a particular asthma phenotype, but also the mechanisms underlying the immunopathologic process. Within such a framework, we propose alternate components of exposomic investigation of asthma in which, the exposome represents a reiterative investigative process of targeted biomarker identification, validation through computational systems biology and physical sampling of environmental medi

A Continuous Process for the Glycerolysis of Soybean Oil

A continuous process for the glycerolysis of soybean oil with pure and crude glycerol, the co-product from the transesterification of soybean oil was investigated in a pilot plant. The process was equipped with a motionless and a high-shear mixer. The experimental studies explored the effects of variations in mixing intensity, temperature, reactant flow rates, and reactant stoichiometry on the formation of MG and DC. The developed process resulted in high conversion of TC to MC. The most favorable conditions were 230°C, 40 mL/min total flow, 25 mm of reaction time, 2.5:1 molar ratio of glycerol/soybean oil, and 3600 rpm for the reactions involving crude glycerol where the concentrations of MC and DC in the product were about 56 and 36 wt%, respectively. Under similar conditions, glycerolysis of pure glycerol resulted in 58% MC and 33% DC. In general, higher temperatures and mixing intensities favored the conversion of TC to MC and DC. Reaction temperature had a greater influence on the extent of the reaction than mixing. The formation of MC approached equilibrium for nearly all cases under investigations

Molecular characterization, expression in Escherichia coli, and epitope analysis of a two EF-hand calcium-binding birch pollen allergen, Bet v 4

Birch pollen belongs to the most potent elicitors of Type I allergic reactions in early spring. Using serum IgE from a birch pollen allergic patient, two cDNA clones (clone 6 and clone 13) were isolated hom a birch pollen expression cDNA library constructed in phage lambda gt11. Clone 6 encoded a 9.3 kD two EF-hand calcium-binding protein, designated Bet v 4, with significant end to end sequence homology to EF-hand calcium-binding allergens from weed and grass pollen. Recombinant Bet v 4, expressed as beta-galactosidase fusion protein, reacted with serum IgE from approximately 20% of pollen allergic individuals. Depletion of allergen-bound calcium by EGTA treatment lead to a substantial reduction of IgE-binding to Bet v 4, indicating that protein-bound calcium is necessary for the maintenance of IgE-epitopes. The greatly reduced IgE-binding capacity of clone 13, a Bet v 4 fragment that lacked the 16 N-terminal amino acids, indicated that the N-terminus contributes significantly to the proteins IgE-binding capacity. By IgE-inhibition experiments it was demonstrated that recombinant Bet v 4 shared IgE-epitopes with natural Bet v 4 and a homologous timothy grass pollen allergen. Recombinant Bet v 4 may therefore be considered as a relevant crossreactive plant allergen, which may be used for diagnosis and treatment of patients suffering from multivalent plant allergies. (C) 1997 Academic Press

OTOLITH MICROCHEMISTRY INDICATES UNEXPECTED PATTERNS OF RESIDENCY AND ANADROMY IN BLUEBACK HERRING, ALOSA AESTIVALIS, IN THE HUDSON AND MOHAWK RIVERS.

Blueback herring is an anadromous fish endemic in the tidal Hudson River Estuary, USA. Twentieth-century improvements to a lock and canal system permitted the species to invade the Hudson’s main tributary, the Mohawk River, where it has been recorded since the 1930s. Moving westward over time, individuals were collected in Lake Ontario, approx. 275 km west of the Hudson, in 1997. However, the actual status (resident or marine anadromous) of adults there or in the Mohawk has not been determined. We collected adult blueback herring in the spring 1999 spawning run and analyzed their otoliths’ elemental composition with both electron (WDS) and nuclear (mu PIXE) microprobes. We measured strontium:calcium ratios along « life-history transects » (WDS) and mapped entire otoliths (mu PIXE), providing a detailed time series of data on the Sr:Ca, and thus habitat use history, of the fish. We also analyzed otoliths of Mohawk and Hudson River young-of-year (YOY). The Sr:Ca ratios of Mohawk YOY are slightly but significantly higher than those of Hudson YOY. Life history transects for 51 adults show complex patterns of Sr:Ca, indicating that many of the fish move into salt water at least for brief periods. However, many fish appear to spend extended parts of their post-YOY lives in fresh water, and at least two adults (caught in the Mohawk near Rome, NY) appear never to have changed habitats at all. This is thus the first demonstration of residency in Mohawk River herring

OTOLITH MICROCHEMISTRY INDICATES UNEXPECTED PATTERNS OF RESIDENCY AND ANADROMY IN BLUEBACK HERRING, ALOSA AESTIVALIS, IN THE HUDSON AND MOHAWK RIVERS.

Blueback herring is an anadromous fish endemic in the tidal Hudson River Estuary, USA. Twentieth-century improvements to a lock and canal system permitted the species to invade the Hudson’s main tributary, the Mohawk River, where it has been recorded since the 1930s. Moving westward over time, individuals were collected in Lake Ontario, approx. 275 km west of the Hudson, in 1997. However, the actual status (resident or marine anadromous) of adults there or in the Mohawk has not been determined. We collected adult blueback herring in the spring 1999 spawning run and analyzed their otoliths’ elemental composition with both electron (WDS) and nuclear (mu PIXE) microprobes. We measured strontium:calcium ratios along « life-history transects » (WDS) and mapped entire otoliths (mu PIXE), providing a detailed time series of data on the Sr:Ca, and thus habitat use history, of the fish. We also analyzed otoliths of Mohawk and Hudson River young-of-year (YOY). The Sr:Ca ratios of Mohawk YOY are slightly but significantly higher than those of Hudson YOY. Life history transects for 51 adults show complex patterns of Sr:Ca, indicating that many of the fish move into salt water at least for brief periods. However, many fish appear to spend extended parts of their post-YOY lives in fresh water, and at least two adults (caught in the Mohawk near Rome, NY) appear never to have changed habitats at all. This is thus the first demonstration of residency in Mohawk River herring